One of the goals of this project is to understand the mechanisms by which contraction is initiated and controlled by potential changes of the membranous system of skeletal muscle. Particularly, we will explore the electrical and membranous properties of the transverse tubular system (T-system) of skeletal muscle. We also plan to study the mechanism of calcium release from the sarcoplasmic reticulum using skinned muscle fibers. Another goal of this project is to investigate the coding process of the crustacean stretch receptor organ. We will use electrophysiological techniques as well as the fluorescence dye technique to measure membrane potentials. BIBLIOGRAPHIC REFERENCES: Gilai, A. and Nakajima, S. (1976). Dye absorption changes during excitation of single amphibian muscle fibers. Biophys. J. 16: 153a. Nakajima, S., Gilai, A., and Dingeman, D. (1976). Dye absorption changes in single muscle fibers: an application of an automatic balancing circuit. Pflugers Arch. 362: 285-287.